LM75B. 1. General description. 2. Features and benefits. Digital temperature sensor and thermal watchdog

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1 Rev February 2015 Product data sheet 1. General description The is a temperature-to-digital converter using an on-chip band gap temperature sensor and Sigma-Delta A-to-D conversion technique with an overtemperature detection output. The contains a number of data registers: Configuration register (Conf) to store the device settings such as device operation mode, OS operation mode, OS polarity and OS fault queue as described in Section 7 Functional description ; temperature register (Temp) to store the digital temp reading, and set-point registers (Tos and Thyst) to store programmable overtemperature shutdown and hysteresis limits, that can be communicated by a controller via the 2-wire serial I 2 C-bus interface. The device also includes an open-drain output (OS) which becomes active when the temperature exceeds the programmed limits. There are three selectable logic address pins so that eight devices can be connected on the same bus without address conflict. The can be configured for different operation conditions. It can be set in normal mode to periodically monitor the ambient temperature, or in shutdown mode to minimize power consumption. The OS output operates in either of two selectable modes: OS comparator mode or OS interrupt mode. Its active state can be selected as either HIGH or LOW. The fault queue that defines the number of consecutive faults in order to activate the OS output is programmable as well as the set-point limits. The temperature register always stores an 11-bit two s complement data giving a temperature resolution of C. This high temperature resolution is particularly useful in applications of measuring precisely the thermal drift or runaway. When the is accessed the conversion in process is not interrupted (that is, the I 2 C-bus section is totally independent of the Sigma-Delta converter section) and accessing the continuously without waiting at least one conversion time between communications will not prevent the device from updating the Temp register with a new conversion result. The new conversion result will be available immediately after the Temp register is updated. The powers up in the normal operation mode with the OS in comparator mode, temperature threshold of 80 C and hysteresis of 75 C, so that it can be used as a stand-alone thermostat with those pre-defined temperature set points. 2. Features and benefits Pin-for-pin replacement for industry standard LM75 and LM75A and offers improved temperature resolution of C and specification of a single part over power supply range from 2.8 V to 5.5 V I 2 C-bus interface with up to 8 devices on the same bus Power supply range from 2.8 V to 5.5 V Temperatures range from 55 C to +125 C

2 3. Applications Frequency range 20 Hz to 400 khz with bus fault time-out to prevent hanging up the bus 11-bit ADC that offers a temperature resolution of C Temperature accuracy of: 2 C from 25 C to +100 C 3 C from 55 C to +125 C Programmable temperature threshold and hysteresis set points Supply current of 1.0 A in shutdown mode for power conservation Stand-alone operation as thermostat at power-up ESD protection exceeds 4500 V HBM per JESD22-A114 and 1000 V CDM per JESD22-C101 Latch-up testing is done to JEDEC Standard JESD78 which exceeds 100 ma Small 8-pin package types: SO8, TSSOP8, 3 mm 2 mm XSON8U, and 2mm 3mmHWSON8 System thermal management Personal computers Electronics equipment Industrial controllers All information provided in this document is subject to legal disclaimers. NXP B.V All rights reserved. Product data sheet Rev February of 37

3 4. Ordering information Table 1. Ordering information Type number Topside mark Package Name Description Version D D SO8 plastic small outline package; 8 leads; body width 3.9 mm SOT96-1 DP TSSOP8 plastic thin shrink small outline package; 8 leads; body width 3 mm SOT505-1 GD [1] 75B XSON8U plastic extremely thin small outline package; no leads; 8 terminals; SOT996-2 UTLP based; body mm TP M75 HWSON8 plastic thermal enhanced very very thin small outline package; no leads; 8 terminals, mm SOT [1] GD cannot be production cold temperature tested because of manufacturing process constraints. Although no GD complaints have been noted, NXP recommends consideration/use of the TP instead of the GD in operating environments of less than 0 C. Table 2. Ordering options Type number Orderable part number 4.1 Ordering options Package Packing method Minimum order quantity Temperature D D,112 SO8 Standard marking * IC s tube T amb = 55 C to +125 C DSC bulk pack D,118 SO8 Reel 13 Q1/T T amb = 55 C to +125 C *Standard mark SMD DP DP,118 TSSOP8 Reel 13 Q1/T T amb = 55 C to +125 C *Standard mark SMD GD GD,125 XSON8U Reel 7 Q3/T4 *Standard mark 3000 T amb = 55 C to +125 C TP TP,147 HWSON8 Reel 7 Q2/T3 *Standard mark 4000 T amb = 55 C to +125 C All information provided in this document is subject to legal disclaimers. NXP B.V All rights reserved. Product data sheet Rev February of 37

4 5. Block diagram V CC BIAS REFERENCE POINTER REGISTER CONFIGURATION REGISTER BAND GAP TEMP SENSOR OSCILLATOR POWER-ON RESET 11-BIT SIGMA-DELTA A-to-D CONVERTER COUNTER TIMER COMPARATOR/ INTERRUPT TEMPERATURE REGISTER TOS REGISTER THYST REGISTER OS LOGIC CONTROL AND INTERFACE 002aad453 A2 A1 A0 SCL SDA GND Fig 1. Block diagram of 6. Pinning information 6.1 Pinning SDA SCL OS D V CC A0 A1 SDA SCL OS DP V CC A0 A1 GND 4 5 A2 GND 4 5 A2 002aad aad455 Fig 2. Pin configuration for SO8 Fig 3. Pin configuration for TSSOP8 SDA SCL OS GD V CC A0 A1 terminal 1 index area SDA SCL OS TP V CC A0 A1 GND 4 5 A2 GND 4 5 A2 Transparent top view 002aae234 Transparent top view 002aag155 Fig 4. Pin configuration for XSON8U Fig 5. Pin configuration for HWSON8 All information provided in this document is subject to legal disclaimers. NXP B.V All rights reserved. Product data sheet Rev February of 37

5 6.2 Pin description 7. Functional description Table 3. Pin description Symbol Pin Description SDA 1 Digital I/O. I 2 C-bus serial bidirectional data line; open-drain. SCL 2 Digital input. I 2 C-bus serial clock input. OS 3 Overtemperature Shutdown output; open-drain. GND 4 Ground. To be connected to the system ground. A2 5 Digital input. User-defined address bit 2. A1 6 Digital input. User-defined address bit 1. A0 7 Digital input. User-defined address bit 0. V CC 8 Power supply. 7.1 General operation The uses the on-chip band gap sensor to measure the device temperature with the resolution of C and stores the 11-bit two s complement digital data, resulted from 11-bit A-to-D conversion, into the device Temp register. This Temp register can be read at any time by a controller on the I 2 C-bus. Reading temperature data does not affect the conversion in progress during the read operation. The device can be set to operate in either mode: normal or shutdown. In normal operation mode, the temp-to-digital conversion is executed every 100 ms and the Temp register is updated at the end of each conversion. During each conversion period (T conv ) of about 100 ms the device takes only about 10 ms, called temperature conversion time (t conv(t) ), to complete a temperature-to-data conversion and then becomes idle for the time remaining in the period. This feature is implemented to significantly reduce the device power dissipation. In shutdown mode, the device becomes idle, data conversion is disabled and the Temp register holds the latest result; however, the device I 2 C-bus interface is still active and register write/read operation can be performed. The device operation mode is controllable by programming bit B0 of the configuration register. The temperature conversion is initiated when the device is powered-up or put back into normal mode from shutdown. In addition, at the end of each conversion in normal mode, the temperature data (or Temp) in the Temp register is automatically compared with the overtemperature shutdown threshold data (or T th(ots) ) stored in the Tos register, and the hysteresis data (or T hys ) stored in the Thyst register, in order to set the state of the device OS output accordingly. The device Tos and Thyst registers are write/read capable, and both operate with 9-bit two s complement digital data. To match with this 9-bit operation, the Temp register uses only the 9 MSB bits of its 11-bit data for the comparison. The way that the OS output responds to the comparison operation depends upon the OS operation mode selected by configuration bit B1, and the user-defined fault queue defined by configuration bits B3 and B4. All information provided in this document is subject to legal disclaimers. NXP B.V All rights reserved. Product data sheet Rev February of 37

6 In OS comparator mode, the OS output behaves like a thermostat. It becomes active when the Temp exceeds the T th(ots), and is reset when the Temp drops below the T hys. Reading the device registers or putting the device into shutdown does not change the state of the OS output. The OS output in this case can be used to control cooling fans or thermal switches. In OS interrupt mode, the OS output is used for thermal interruption. When the device is powered-up, the OS output is first activated only when the Temp exceeds the T th(ots) ; then it remains active indefinitely until being reset by a read of any register. Once the OS output has been activated by crossing T th(ots) and then reset, it can be activated again only when the Temp drops below the T hys ; then again, it remains active indefinitely until being reset by a read of any register. The OS interrupt operation would be continued in this sequence: T th(ots) trip, Reset, T hys trip, Reset, T th(ots) trip, Reset, T hys trip, Reset, etc. Putting the device into the shutdown mode by setting the bit 0 of the configuration register also resets the OS output. In both cases, comparator mode and interrupt mode, the OS output is activated only if a number of consecutive faults, defined by the device fault queue, has been met. The fault queue is programmable and stored in the two bits, B3 and B4, of the Configuration register. Also, the OS output active state is selectable as HIGH or LOW by setting accordingly the configuration register bit B2. At power-up, the device is put into normal operation mode, the T th(ots) is set to 80 C, the T hys is set to 75 C, the OS active state is selected LOW and the fault queue is equal to 1. The temp reading data is not available until the first conversion is completed in about 100 ms. The OS response to the temperature is illustrated in Figure 6. T th(ots) T hys OS reset reading temperature limits OS active OS output in comparator mode OS reset (1) (1) (1) OS active OS output in interrupt mode 002aae334 (1) OS is reset by either reading register or putting the device in shutdown mode. It is assumed that the fault queue is met at each T th(ots) and T hys crossing point. Fig 6. OS response to temperature All information provided in this document is subject to legal disclaimers. NXP B.V All rights reserved. Product data sheet Rev February of 37

7 7.2 I 2 C-bus serial interface The can be connected to a compatible 2-wire serial interface I 2 C-bus as a slave device under the control of a controller or master device, using two device terminals, SCL and SDA. The controller must provide the SCL clock signal and write/read data to/from the device through the SDA terminal. Notice that if the I 2 C-bus common pull-up resistors have not been installed as required for I 2 C-bus, then an external pull-up resistor, about 10 k, is needed for each of these two terminals. The bus communication protocols are described in Section Bus fault time-out If the SDA line is held LOW for longer than t to (75 ms minimum / 13.3 Hz; guaranteed at 50 ms minimum / 20 Hz), the will reset to the idle state (SDA released) and wait for a new START condition. This ensures that the will never hang up the bus should there be conflict in the transmission sequence. 7.3 Slave address The slave address on the I 2 C-bus is partially defined by the logic applied to the device address pins A2, A1 and A0. Each of them is typically connected either to GND for logic 0, or to V CC for logic 1. These pins represent the three LSB bits of the device 7-bit address. The other four MSB bits of the address data are preset to 1001 by hard wiring inside the. Table 4 shows the device s complete address and indicates that up to 8 devices can be connected to the same bus without address conflict. Because the input pins, SCL, SDA and A2 to A0, are not internally biased, it is important that they should not be left floating in any application. Table 4. Address table 1 = HIGH; 0 = LOW. MSB LSB A2 A1 A0 7.4 Register list The contains four data registers beside the pointer register as listed in Table 5. The pointer value, read/write capability and default content at power-up of the registers are also shown in Table 5. Table 5. Register name Register table Pointer R/W value POR state Description Conf 01h R/W 00h Configuration register: contains a single 8-bit data byte; to set the device operating condition; default = 0. Temp 00h read only n/a Temperature register: contains two 8-bit data bytes; to store the measured Temp data. Tos 03h R/W 5000h Overtemperature shutdown threshold register: contains two 8-bit data bytes; to store the overtemperature shutdown T th(ots) limit; default = 80 C. Thyst 02h R/W 4B00h Hysteresis register: contains two 8-bit data bytes; to store the hysteresis T hys limit; default = 75 C. All information provided in this document is subject to legal disclaimers. NXP B.V All rights reserved. Product data sheet Rev February of 37

8 7.4.1 Pointer register The Pointer register contains an 8-bit data byte, of which the two LSB bits represent the pointer value of the other four registers, and the other 6 MSB bits are equal to 0, as shown in Table 6 and Table 7. The Pointer register is not accessible to the user, but is used to select the data register for write/read operation by including the pointer data byte in the bus command. Table 6. Pointer register B7 B6 B5 B4 B3 B2 B[1:0] pointer value Table 7. Pointer value B1 B0 Selected register 0 0 Temperature register (Temp) 0 1 Configuration register (Conf) 1 0 Hysteresis register (Thyst) 1 1 Overtemperature shutdown register (Tos) Because the Pointer value is latched into the Pointer register when the bus command (which includes the pointer byte) is executed, a read from the may or may not include the pointer byte in the statement. To read again a register that has been recently read and the pointer has been preset, the pointer byte does not have to be included. To read a register that is different from the one that has been recently read, the pointer byte must be included. However, a write to the must always include the pointer byte in the statement. The bus communication protocols are described in Section At power-up, the Pointer value is equal to 00 and the Temp register is selected; users can then read the Temp data without specifying the pointer byte. However, the first temperature reading will be incorrect and must be ignored. Subsequent reads of the temperature register will be correct Configuration register The Configuration register (Conf) is a write/read register and contains an 8-bit non-complement data byte that is used to configure the device for different operation conditions. Table 8 shows the bit assignments of this register. Table 8. Conf register Legend: * = default value. Bit Symbol Access Value Description B[7:5] reserved R/W 000* reserved for manufacturer s use; should be kept as zeroes for normal operation B[4:3] OS_F_QUE[1:0] R/W OS fault queue programming 00* queue value = 1 01 queue value = 2 10 queue value = 4 11 queue value = 6 All information provided in this document is subject to legal disclaimers. NXP B.V All rights reserved. Product data sheet Rev February of 37

9 Table 8. Conf register continued Legend: * = default value. Bit Symbol Access Value Description B2 OS_POL R/W OS polarity selection 0* OS active LOW 1 OS active HIGH B1 OS_COMP_INT R/W OS operation mode selection 0* OS comparator 1 OS interrupt B0 SHUTDOWN R/W device operation mode selection 0* normal 1 shutdown Temperature register The Temperature register (Temp) holds the digital result of temperature measurement or monitor at the end of each analog-to-digital conversion. This register is read-only and contains two 8-bit data bytes consisting of one Most Significant Byte (MSByte) and one Least Significant Byte (LSByte). However, only 11 bits of those two bytes are used to store the Temp data in two s complement format with the resolution of C. Table 9 shows the bit arrangement of the Temp data in the data bytes. Table 9. Temp register MSByte LSByte D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 X X X X X When reading register Temp, all 16 bits of the two data bytes (MSByte and LSByte) are provided to the bus and must be all collected by the controller to complete the bus operation. However, only the 11 most significant bits should be used, and the 5 least significant bits of the LSByte are zero and should be ignored. One of the ways to calculate the Temp value in C from the 11-bit Temp data is: 1. If the Temp data MSByte bit D10 = 0, then the temperature is positive and Temp value ( C) = +(Temp data) C. 2. If the Temp data MSByte bit D10 = 1, then the temperature is negative and Temp value ( C) = (two s complement of Temp data) C. Examples of the Temp data and value are shown in Table 10. Table 10. Temp register value 11-bit binary Hexadecimal value Decimal value Value (two s complement) F C F C F C E C C C C All information provided in this document is subject to legal disclaimers. NXP B.V All rights reserved. Product data sheet Rev February of 37

10 Table 10. Temp register value continued 11-bit binary (two s complement) Hexadecimal value Decimal value Value C FF C C C C For 9-bit Temp data application in replacing the industry standard LM75, just use only 9 MSB bits of the two bytes and disregard 7 LSB of the LSByte. The 9-bit Temp data with 0.5 C resolution of the is defined exactly in the same way as for the standard LM75 and it is here similar to the Tos and Thyst registers. The only MSByte of the temperature can also be read with the use of a one-byte reading command. Then the temperature resolution will be 1.00 C instead Overtemperature shutdown threshold (Tos) and hysteresis (Thyst) registers These two registers, are write/read registers, and also called set-point registers. They are used to store the user-defined temperature limits, called overtemperature shutdown threshold (T th(ots) ) and hysteresis temperature (T hys ), for the device watchdog operation. At the end of each conversion the Temp data will be compared with the data stored in these two registers in order to set the state of the device OS output; see Section 7.1. Each of the set-point registers contains two 8-bit data bytes consisting of one MSByte and one LSByte the same as register Temp. However, only 9 bits of the two bytes are used to store the set-point data in two s complement format with the resolution of 0.5 C. Table 11 and Table 12 show the bit arrangement of the Tos data and Thyst data in the data bytes. Notice that because only 9-bit data are used in the set-point registers, the device uses only the 9 MSB of the Temp data for data comparison. Table 11. Tos register MSByte LSByte D8 D7 D6 D5 D4 D3 D2 D1 D0 X X X X X X X Table 12. Thyst register MSByte LSByte D8 D7 D6 D5 D4 D3 D2 D1 D0 X X X X X X X When a set-point register is read, all 16 bits are provided to the bus and must be collected by the controller to complete the bus operation. However, only the 9 most significant bits should be used and the 7 LSB of the LSByte are equal to zero and should be ignored. Table 13 shows examples of the limit data and value. All information provided in this document is subject to legal disclaimers. NXP B.V All rights reserved. Product data sheet Rev February of 37

11 Table 13. Tos and Thyst limit data and value 11-bit binary Hexadecimal value Decimal value Value (two s complement) FA C C C C FF C CE C C 7.5 OS output and polarity The OS output is an open-drain output and its state represents results of the device watchdog operation as described in Section 7.1. In order to observe this output state, an external pull-up resistor is needed. The resistor should be as large as possible, up to 200 k, to minimize the Temp reading error due to internal heating by the high OS sinking current. The OS output active state can be selected as HIGH or LOW by programming bit B2 (OS_POL) of register Conf: setting bit OS_POL to logic 1 selects OS active HIGH and setting bit B2 to logic 0 sets OS active LOW. At power-up, bit OS_POL is equal to logic 0 and the OS active state is LOW. 7.6 OS comparator and interrupt modes As described in Section 7.1, the device OS output responds to the result of the comparison between register Temp data and the programmed limits, in registers Tos and Thyst, in different ways depending on the selected OS mode: OS comparator or OS interrupt. The OS mode is selected by programming bit B1 (OS_COMP_INT) of register Conf: setting bit OS_COMP_INT to logic 1 selects the OS interrupt mode, and setting to logic 0 selects the OS comparator mode. At power-up, bit OS_COMP_INT is equal to logic 0 and the OS comparator is selected. The main difference between the two modes is that in OS comparator mode, the OS output becomes active when Temp has exceeded T th(ots) and reset when Temp has dropped below T hys, reading a register or putting the device into shutdown mode does not change the state of the OS output; while in OS interrupt mode, once it has been activated either by exceeding T th(ots) or dropping below T hys, the OS output will remain active indefinitely until reading a register, then the OS output is reset. Temperature limits T th(ots) and T hys must be selected so that T th(ots) > T hys. Otherwise, the OS output state will be undefined. All information provided in this document is subject to legal disclaimers. NXP B.V All rights reserved. Product data sheet Rev February of 37

12 7.7 OS fault queue Fault queue is defined as the number of faults that must occur consecutively to activate the OS output. It is provided to avoid false tripping due to noise. Because faults are determined at the end of data conversions, fault queue is also defined as the number of consecutive conversions returning a temperature trip. The value of fault queue is selectable by programming the two bits B4 and B3 (OS_F_QUE[1:0]) in register Conf. Notice that the programmed data and the fault queue value are not the same. Table 14 shows the one-to-one relationship between them. At power-up, fault queue data = 0 and fault queue value = 1. Table 14. Fault queue table Fault queue data Fault queue value OS_F_QUE[1] OS_F_QUE[0] Decimal Shutdown mode The device operation mode is selected by programming bit B0 (SHUTDOWN) of register Conf. Setting bit SHUTDOWN to logic 1 will put the device into shutdown mode. Resetting bit SHUTDOWN to logic 0 will return the device to normal mode. In shutdown mode, the device draws a small current of approximately 1.0 A and the power dissipation is minimized; the temperature conversion stops, but the I 2 C-bus interface remains active and register write/read operation can be performed. When the shutdown is set, the OS output will be unchanged in comparator mode and reset in interrupt mode. 7.9 Power-up default and power-on reset The always powers-up in its default state with: Normal operation mode OS comparator mode T th(ots) = 80 C T hys = 75 C OS output active state is LOW Pointer value is logic 00 (Temp) When the power supply voltage is dropped below the device power-on reset level of approximately 1.0 V (POR) for over 2 s and then rises up again, the device will be reset to its default condition as listed above. All information provided in this document is subject to legal disclaimers. NXP B.V All rights reserved. Product data sheet Rev February of 37

13 7.10 Protocols for writing and reading the registers The communication between the host and the must strictly follow the rules as defined by the I 2 C-bus management. The protocols for register read/write operations are illustrated in Figure 7 to Figure 12 together with the following definitions: 1. Before a communication, the I 2 C-bus must be free or not busy. It means that the SCL and SDA lines must both be released by all devices on the bus, and they become HIGH by the bus pull-up resistors. 2. The host must provide SCL clock pulses necessary for the communication. Data is transferred in a sequence of 9 SCL clock pulses for every 8-bit data byte followed by 1-bit status of the acknowledgement. 3. During data transfer, except the START and STOP signals, the SDA signal must be stable while the SCL signal is HIGH. It means that the SDA signal can be changed only during the LOW duration of the SCL line. 4. S: START signal, initiated by the host to start a communication, the SDA goes from HIGH to LOW while the SCL is HIGH. 5. RS: RE-START signal, same as the START signal, to start a read command that follows a write command. 6. P: STOP signal, generated by the host to stop a communication, the SDA goes from LOW to HIGH while the SCL is HIGH. The bus becomes free thereafter. 7. W: write bit, when the write/read bit = LOW in a write command. 8. R: read bit, when the write/read bit = HIGH in a read command. 9. A: device acknowledge bit, returned by the. It is LOW if the device works properly and HIGH if not. The host must release the SDA line during this period in order to give the device the control on the SDA line. 10. A : master acknowledge bit, not returned by the device, but set by the master or host in reading 2-byte data. During this clock period, the host must set the SDA line to LOW in order to notify the device that the first byte has been read for the device to provide the second byte onto the bus. 11. NA: Not Acknowledge bit. During this clock period, both the device and host release the SDA line at the end of a data transfer, the host is then enabled to generate the STOP signal. 12. In a write protocol, data is sent from the host to the device and the host controls the SDA line, except during the clock period when the device sends the device acknowledgement signal to the bus. 13. In a read protocol, data is sent to the bus by the device and the host must release the SDA line during the time that the device is providing data onto the bus and controlling the SDA line, except during the clock period when the master sends the master acknowledgement signal to the bus. All information provided in this document is subject to legal disclaimers. NXP B.V All rights reserved. Product data sheet Rev February of 37

14 SCL SDA S A2 A1 A0 W A A D4 D3 D2 D1 D0 A P START device address pointer byte configuration data byte write device acknowledge device acknowledge device acknowledge STOP 001aad624 Fig 7. Write configuration register (1-byte data) SCL (next) SDA S A2 A1 A0 W A A RS (next) device address pointer byte START write device acknowledge device acknowledge RE-START SCL (cont.) SDA (cont.) A2 A1 A0 R A D7 D6 D5 D4 D3 D2 D1 D0 NA P device address read device acknowledge data byte from device master not acknowledged STOP 001aad625 Fig 8. Read configuration register including pointer byte (1-byte data) SCL SDA S A2 A1 A0 R A D7 D6 D5 D4 D3 D2 D1 D0 NA P device address data byte from device START read device acknowledge master not acknowledged STOP 001aad626 Fig 9. Read configuration or temp register with preset pointer (1-byte data) All information provided in this document is subject to legal disclaimers. NXP B.V All rights reserved. Product data sheet Rev February of 37

15 SCL (next) SDA S A2 A1 A0 W A P1 P0 A (next) device address pointer byte START write device device acknowledge acknowledge SCL (cont.) SDA (cont.) D7 D6 D5 D4 D3 D2 D1 D0 A D7 D6 D5 D4 D3 D2 D1 D0 A P MSByte data device acknowledge LSByte data device acknowledge STOP 002aad036 Fig 10. Write Tos or Thyst register (2-byte data) SCL (next) SDA S A2 A1 A0 W A P1 P0 A RS (next) SCL (cont) SDA (cont) device address pointer byte START write device RE-START device acknowledge acknowledge A2 A1 A0 R A D7 D6 D5 D4 D3 D2 D1 D0 A' D7 D6 D5 D4 D3 D2 D1 D0 NA P device address MSByte from device LSByte from device read device acknowledge master acknowledge master not acknowledged STOP 002aad037 Fig 11. Read Temp, Tos or Thyst register including pointer byte (2-byte data) SCL SDA S A2 A1 A0 R A D7 D6 D5 D4 D3 D2 D1 D0 A' D7 D6 D5 D4 D3 D2 D1 D0 NA P device address MSByte from device LSByte from device START read master device acknowledge acknowledge master not acknowledged STOP 002aad038 Fig 12. Read Temp, Tos or Thyst register with preset pointer (2-byte data) All information provided in this document is subject to legal disclaimers. NXP B.V All rights reserved. Product data sheet Rev February of 37

16 8. Application design-in information 8.1 Typical application power supply 0.1 μf BUS 10 kω PULL-UP RESISTORS I 2 C-BUS 10 kω SCL SDA 2 1 V CC 8 10 kω DIGITAL LOGIC A2 A1 A OS DETECTOR OR INTERRUPT LINE GND 002aad457 Fig 13. Typical application Table LM75A and comparison LM75A and comparison Description LM75A availability of the XSON8U (3 mm 2 mm) package type no yes OS output auto-reset when SHUTDOWN bit is set in interrupt mode [1] no yes support single-byte reading of the Temp registers without bus lockup [2] no yes bus fault time-out (75 ms, 200 ms) [3] no yes minimum data hold time (t HD;DAT ) [4] 10 ns 0 ns ratio of conversion time / conversion period (typical) [5] 100 ms / 100 ms 10 ms / 100 ms supply current in shutdown mode (typical value) 3.5 A 0.2 A HBM ESD protection level (minimum) >2000 V >4500 V MM ESD protection level (minimum) >200 V >450 V CDM ESD protection level (minimum) >1000 V >2000 V [1] This option is updated to be compatible with the competitive parts. When the OS output has been activated in the interrupt mode due to a temp limit violation, if the Configuration Shutdown bit B0 is set (to the LM75A), then the OS output activated status remains unchanged, while (to the ) the OS will be reset. The latter is compatible with the operation condition of the competitive parts. [2] The LM75 series is intentionally designed to provide two successive temperature data bytes (MSByte and LSByte) for the 11-bit data resolution and both bytes should be read in a typical application. In some specific applications, when only the MSByte is read using a single-byte read command, it often happens that if bit D7 of the LSByte is zero, then the device will hold the SDA bus in a LOW state forever, resulting in a bus hang-up problem, and the bus cannot be released until the device power is reset. This condition exists for the LM75A but not for the. For the the temperature can be read either one byte or two bytes without a hang-up problem. [3] The bus time-out is included for releasing the device operation whenever the SDA input is kept at a LOW state for too long (longer than the time-out duration) due to a fault from the host. The trade-off for this option is the limitation of the I 2 C-bus low frequency operation to be limited to 20 Hz. This option is compatible with some of the latest versions of the competitive parts. [4] The data hold time is improved to increase the timing margin in I 2 C-bus operation. All information provided in this document is subject to legal disclaimers. NXP B.V All rights reserved. Product data sheet Rev February of 37

17 [5] The performs the temperature-to-data conversions with a much higher speed than the LM75A. While the LM75A takes almost the whole of conversion period (T conv ) time of about 100 ms to complete a conversion, the takes only about 1 10 of the period, or about 10 ms. Therefore, the conversion period (T conv ) is the same, but the temperature conversion time (t conv(t) ) is different between the two parts. A shorter conversion time is applied to significantly reduce the device s average power dissipation. During each conversion period, when the conversion is completed, the becomes idled and the power is reduced, resulting in a lesser average power consumption. 8.3 Temperature accuracy Because the local channel of the temperature sensor measures its own die temperature that is transferred from its body, the temperature of the device body must be stabilized and saturated for it to provide the stable readings. Because the operates at a low power level, the thermal gradient of the device package has a minor effect on the measurement. The accuracy of the measurement is more dependent upon the definition of the environment temperature, which is affected by different factors: the printed-circuit board on which the device is mounted; the air flow contacting the device body (if the ambient air temperature and the printed-circuit board temperature are much different, then the measurement may not be stable because of the different thermal paths between the die and the environment). The stabilized temperature liquid of a thermal bath will provide the best temperature environment when the device is completely dipped into it. A thermal probe with the device mounted inside a sealed-end metal tube located in consistent temperature air also provides a good method of temperature measurement. If you would like to calculate the effect of self-heating, use Equation 1 below: Equation 1 is the formula to calculate the effect of self-heating: T = R th j-a V DD I V DD AV + OL SDA I V OL sink SDA + OL EVENT I OL sink EVENT (1) where: T = T j T amb T j = junction temperature T amb = ambient temperature R th(j-a) = package thermal resistance V DD = supply voltage I DD(AV) = average supply current V OL(SDA) = LOW-level output voltage on pin SDA V OL(EVENT) = LOW-level output voltage on pin EVENT I OL(sink)(SDA) = SDA output current LOW I OL(sink)EVENT = EVENT output current LOW Calculation example: T amb (typical temperature inside the notebook) = 50 C I DD(AV) = 400 A V DD = 3.6 V Maximum V OL(SDA) = 0.4 V I OL(sink)(SDA) = 1 ma All information provided in this document is subject to legal disclaimers. NXP B.V All rights reserved. Product data sheet Rev February of 37

18 V OL(EVENT) = 0.4 V I OL(sink)EVENT = 3 ma R th(j-a) = 56 C/W Self heating due to power dissipation is: T = = 56 C W 3.04 mw = 0.17 C (2) 8.4 Noise effect The device design includes the implementation of basic features for a good noise immunity: The low-pass filter on both the bus pins SCL and SDA; The hysteresis of the threshold voltages to the bus input signals SCL and SDA, about 500 mv minimum; All pins have ESD protection circuitry to prevent damage during electrical surges. The ESD protection on the address, OS, SCL and SDA pins it to ground. The latch-back based device breakdown voltage of address/os is typically 11 V and SCL/SDA is typically 9.5 V at any supply voltage but will vary over process and temperature. Since there are no protection diodes from SCL or SDA to V CC, the will not hold the I 2 C lines LOW when V CC is not supplied and therefore allow continued I 2 C-bus operation if the is de-powered. However, good layout practices and extra noise filters are recommended when the device is used in a very noisy environment: Use decoupling capacitors at V CC pin. Keep the digital traces away from switching power supplies. Apply proper terminations for the long board traces. Add capacitors to the SCL and SDA lines to increase the low-pass filter characteristics. All information provided in this document is subject to legal disclaimers. NXP B.V All rights reserved. Product data sheet Rev February of 37

19 9. Limiting values Table 16. Limiting values In accordance with the Absolute Maximum Rating System (IEC 60134). Symbol Parameter Conditions Min Max Unit V CC supply voltage V V I input voltage at input pins V I I input current at input pins ma I O(sink) output sink current on pin OS ma V O output voltage on pin OS V T stg storage temperature C T j junction temperature C 10. Recommended operating conditions Table 17. Recommended operating characteristics Symbol Parameter Conditions Min Typ Max Unit V CC supply voltage V T amb ambient temperature C All information provided in this document is subject to legal disclaimers. NXP B.V All rights reserved. Product data sheet Rev February of 37

20 11. Static characteristics Table 18. Static characteristics V CC = 2.8 V to 5.5 V; T amb = 55 C to +125 C; unless otherwise specified. Symbol Parameter Conditions Min Typ [1] Max Unit T acc temperature accuracy T amb = 25 C to +100 C C T amb = 55 C to +125 C C T res temperature resolution 11-bit digital temp data C t conv(t) temperature conversion normal mode ms time T conv conversion period normal mode ms I DD(AV) average supply current normal mode: I 2 C-bus inactive A normal mode: I 2 C-bus active; A f SCL = 400 khz shutdown mode A V IH HIGH-level input voltage digital pins (SCL, SDA, A2 to A0) 0.7 V CC - V CC +0.3 V V IL LOW-level input voltage digital pins V CC V V I(hys) hysteresis of input voltage SCL and SDA pins mv A2, A1, A0 pins mv I IH HIGH-level input current digital pins; V I =V CC A I IL LOW-level input current digital pins; V I = 0 V A V OL LOW-level output voltage SDA and OS pins; I OL =3mA V I OL =4mA V I LO output leakage current SDA and OS pins; V OH =V CC A N fault number of faults programmable; conversions in 1-6 overtemperature-shutdown fault queue T th(ots) overtemperature default value C shutdown threshold temperature T hys hysteresis temperature default value C C i input capacitance digital pins pf [1] Typical values are at V CC = 3.3 V and T amb =25 C. All information provided in this document is subject to legal disclaimers. NXP B.V All rights reserved. Product data sheet Rev February of 37

21 300 I DD(AV) (μa) 200 V CC = 5.5 V 4.5 V 3.3 V 2.8 V 002aae I DD(AV) (μa) 200 V CC = 5.5 V 4.5 V 3.3 V 2.8 V 002aae T amb ( C) T amb ( C) Fig 14. Average supply current versus temperature; I 2 C-bus inactive Fig 15. Average supply current versus temperature; I 2 C-bus active 0.5 I DD(sd) (μa) V CC = 5.5 V 4.5 V 3.3 V 2.8 V 002aae V OL(OS) (V) V CC = 5.5 V 4.5 V 3.3 V 2.8 V 002aae T amb ( C) T amb ( C) Fig 16. Shutdown mode supply current versus temperature Fig 17. LOW-level output voltage on pin OS versus temperature; I OL =4mA 0.5 V OL(SDA) (V) V CC = 5.5 V 4.5 V 3.3 V 2.8 V 002aae202 T acc ( C) aae T amb ( C) T amb ( C) Fig 18. LOW-level output voltage on pin SDA versus temperature; I OL =4mA Fig 19. Typical temperature accuracy versus temperature; V CC =3.3V All information provided in this document is subject to legal disclaimers. NXP B.V All rights reserved. Product data sheet Rev February of 37

22 12. Dynamic characteristics Table 19. I 2 C-bus interface dynamic characteristics [1] V CC = 2.8 V to 5.5 V; T amb = 55 C to +125 C; unless otherwise specified. Symbol Parameter Conditions Min Typ Max Unit f SCL SCL clock frequency see Figure khz t HIGH HIGH period of the SCL clock s t LOW LOW period of the SCL clock s t HD;STA hold time (repeated) START condition ns t SU;DAT data set-up time ns t HD;DAT data hold time ns t SU;STO set-up time for STOP condition ns t f fall time SDA and OS outputs; ns C L = 400 pf; I OL =3mA t to time-out time [2][3] ms [1] These specifications are guaranteed by design and not tested in production. [2] This is the SDA time LOW for reset of serial interface. [3] Holding the SDA line LOW for a time greater than t to will cause the to reset SDA to the idle state of the serial bus communication (SDA set HIGH). SDA 0.7 V DD 0.3 V DD t f t LOW t SU;DAT t r t f t HD;STA t SP t r t BUF SCL 0.7 V DD 0.3 V DD t HD;STA t t HIGH SU;STA t SU;STO S t HD;DAT Sr P S 002aab271 Fig 20. Timing diagram All information provided in this document is subject to legal disclaimers. NXP B.V All rights reserved. Product data sheet Rev February of 37

23 13. Package outline SO8: plastic small outline package; 8 leads; body width 3.9 mm SOT96-1 D E A X c y H E v M A Z 8 5 Q A 2 A 1 (A ) 3 A pin 1 index θ L p 1 4 L e b p w M detail X mm scale DIMENSIONS (inch dimensions are derived from the original mm dimensions) UNIT mm inches A max A 1 A 2 A 3 b p c D (1) E (2) e H (1) E L L p Q v w y Z Notes 1. Plastic or metal protrusions of 0.15 mm (0.006 inch) maximum per side are not included. 2. Plastic or metal protrusions of 0.25 mm (0.01 inch) maximum per side are not included θ o 8 o OUTLINE VERSION REFERENCES IEC JEDEC JEITA EUROPEAN PROJECTION ISSUE DATE SOT E03 MS Fig 21. Package outline SOT96-1 (SO8) All information provided in this document is subject to legal disclaimers. NXP B.V All rights reserved. Product data sheet Rev February of 37

24 TSSOP8: plastic thin shrink small outline package; 8 leads; body width 3 mm SOT505-1 D E A X c y H E v M A Z 8 5 A 2 A1 (A 3 ) A pin 1 index L p θ 1 4 e b p w M L detail X mm scale DIMENSIONS (mm are the original dimensions) A UNIT A max. 1 mm A 2 A 3 b p c D (1) E (2) e H E L L p v w y Z (1) θ Notes 1. Plastic or metal protrusions of 0.15 mm maximum per side are not included. 2. Plastic or metal protrusions of 0.25 mm maximum per side are not included. OUTLINE VERSION REFERENCES IEC JEDEC JEITA EUROPEAN PROJECTION ISSUE DATE SOT Fig 22. Package outline SOT505-1 (TSSOP8) All information provided in this document is subject to legal disclaimers. NXP B.V All rights reserved. Product data sheet Rev February of 37

25 XSON8: plastic extremely thin small outline package; no leads; 8 terminals; body 3 x 2 x 0.5 mm SOT996-2 D B A E A A 1 detail X terminal 1 index area L 1 e 1 e b 1 4 v w C C A B y 1 C C y L 2 L 8 5 X mm scale Dimensions (mm are the original dimensions) Unit (1) A A 1 b D E e e 1 L L 1 L 2 v w y y 1 mm max nom min sot996-2_po Outline version SOT996-2 References IEC JEDEC JEITA European projection Issue date Fig 23. Package outline SOT996-2 (XSON8U) All information provided in this document is subject to legal disclaimers. NXP B.V All rights reserved. Product data sheet Rev February of 37

26 HWSON8: plastic thermal enhanced very very thin small outline package; no leads; 8 terminals; body 2 x 3 x 0.75 mm SOT X D B A E A A 2 A 1 A 3 terminal 1 index area detail X terminal 1 index area e 1 e b 1 4 v w C C A B y 1 C C y L K E 2 8 D 2 5 Dimensions mm scale Unit A (1) A 1 A 2 A 3 b D (1) D 2 E (1) E 2 e e 1 K L v w y y 1 mm max nom min Note 1. Plastic or metal protrusions of mm maximum per side are not included. sot1069-2_po Outline version References IEC JEDEC JEITA SOT MO European projection Issue date Fig 24. Package outline SOT (HWSON8) All information provided in this document is subject to legal disclaimers. NXP B.V All rights reserved. Product data sheet Rev February of 37

27 14. Soldering of SMD packages This text provides a very brief insight into a complex technology. A more in-depth account of soldering ICs can be found in Application Note AN10365 Surface mount reflow soldering description Introduction to soldering Soldering is one of the most common methods through which packages are attached to Printed Circuit Boards (PCBs), to form electrical circuits. The soldered joint provides both the mechanical and the electrical connection. There is no single soldering method that is ideal for all IC packages. Wave soldering is often preferred when through-hole and Surface Mount Devices (SMDs) are mixed on one printed wiring board; however, it is not suitable for fine pitch SMDs. Reflow soldering is ideal for the small pitches and high densities that come with increased miniaturization Wave and reflow soldering Wave soldering is a joining technology in which the joints are made by solder coming from a standing wave of liquid solder. The wave soldering process is suitable for the following: Through-hole components Leaded or leadless SMDs, which are glued to the surface of the printed circuit board Not all SMDs can be wave soldered. Packages with solder balls, and some leadless packages which have solder lands underneath the body, cannot be wave soldered. Also, leaded SMDs with leads having a pitch smaller than ~0.6 mm cannot be wave soldered, due to an increased probability of bridging. The reflow soldering process involves applying solder paste to a board, followed by component placement and exposure to a temperature profile. Leaded packages, packages with solder balls, and leadless packages are all reflow solderable. Key characteristics in both wave and reflow soldering are: Board specifications, including the board finish, solder masks and vias Package footprints, including solder thieves and orientation The moisture sensitivity level of the packages Package placement Inspection and repair Lead-free soldering versus SnPb soldering 14.3 Wave soldering Key characteristics in wave soldering are: Process issues, such as application of adhesive and flux, clinching of leads, board transport, the solder wave parameters, and the time during which components are exposed to the wave Solder bath specifications, including temperature and impurities All information provided in this document is subject to legal disclaimers. NXP B.V All rights reserved. Product data sheet Rev February of 37

28 14.4 Reflow soldering Key characteristics in reflow soldering are: Lead-free versus SnPb soldering; note that a lead-free reflow process usually leads to higher minimum peak temperatures (see Figure 25) than a SnPb process, thus reducing the process window Solder paste printing issues including smearing, release, and adjusting the process window for a mix of large and small components on one board Reflow temperature profile; this profile includes preheat, reflow (in which the board is heated to the peak temperature) and cooling down. It is imperative that the peak temperature is high enough for the solder to make reliable solder joints (a solder paste characteristic). In addition, the peak temperature must be low enough that the packages and/or boards are not damaged. The peak temperature of the package depends on package thickness and volume and is classified in accordance with Table 20 and 21 Table 20. SnPb eutectic process (from J-STD-020D) Package thickness (mm) Package reflow temperature ( C) Volume (mm 3 ) < < Table 21. Lead-free process (from J-STD-020D) Package thickness (mm) Package reflow temperature ( C) Volume (mm 3 ) < to 2000 > 2000 < to > Moisture sensitivity precautions, as indicated on the packing, must be respected at all times. Studies have shown that small packages reach higher temperatures during reflow soldering, see Figure 25. All information provided in this document is subject to legal disclaimers. NXP B.V All rights reserved. Product data sheet Rev February of 37